Hey guys its me again.
So I tried the new caps I got on a second-hand NGC controller that I bought off ebay, which had a really loose left analog stick.
Thanks for your in-depth comparison! I have both of these replacement knobs (A and B), and actually I reached the opposite conclusion as you did. Type A does look a bit better, as it's not as glossy, however the hard surface provides barely any friction, so it's prone to slipping off accidentally.
I personally use Type A only for C-sticks, they work better there for thenar grip than original yellow C-stick knobs, and their low height actually helps not pushing the stick by accident. Even for that, inserting a spacer is necessary, though.
As for the stickbox, from how the F-Zero GX stick response looks like in the video you linked, it seems to me that the potentiometers have a range that's larger than on original potentiometers. That's probably the main reason for why you experience difficulty in doing tilts. The higher stick spring tightness surely added to that, but I'd bet on the potentiometers making up for more.
I think that the xunbeifang stickboxes are much better as replacements: https://www.aliexpress.com/item/10p...e-original-Controller-Repair/32849164738.html
They are just as cheap, with about 1€ per piece, and they actually use original potentiometers. There's even a chance that they were used in original Nintendo products, namely Nunchuks, as they are frequently found in these, however it's difficult to say whether they were really put in there at the Mitsumi (?) factory or whether someone services Nunchuks in huge quantities and always puts in these stickboxes.
Still, like I wrote before, the xunbeifang / Type 4 stickboxes are not lubricated and have mediocre notch accuracy. So, after lubricating them a little bit (for longevity), they are okay when playing on UCF or Smash 4, but on vanilla Melee, not so much.
About the conductive pads, I measured their force resistance, and the L/R pads have only about 3 N click resistance – original new ones have 5 N. I personally think that 3 N are much better, however it contradicts your claim that they are "more springy" than new Smash 4 controllers (which range from 4.7 to 5.5 N, in my measurements).